Previous studies have shown that the event which immediately led to injury was slip in about 50% of the cases. This type of underfoot "first event" has been the main contributor to falls. The proposed four year study provides an experimental design which has the potential for investigating the interaction between age, sex and other fall risk factors such as surface slipperiness, shoe wear/tear, and lighting. In the proposed study, gait and postural instability and fall potential of all risk factors will be evaluated for 94 industrial workers' (21 to 70 years of age) task performance on a slippery surface. These tasks simulate conditions which occur in nonoccupational and occupational environments while standing or walking on a slippery surface. The proposed study is designed to test the following hypotheses: (a) The subject's ability to correctly assess the slipperiness of a surface will be impaired in a poorly-lighted condition. (b) The subject's ability to correctly assess the slipperiness of a surface will be impaired if the shoe sole surface does not make proper contact (due to wear/tear and/or leg muscle strength) and doesn't produce sufficient contact pressure. (c) The subject's ability to correctly assess the slipperiness of a surface will be poorer in the older subjects compared to the younger group. (d) The effect of environmental lighting, job-task, shoe sole wear/tear, and age will have their most detrimental impact on subject's ability to perform the task requiring dynamic postural control during gait compared to the static task performance. (e) The effect of training on a known slippery surface will have beneficial outcome in terms of task performance and reduced fall potential. The findings from this study will provide quantitative data regarding how the above risk factors influence fall/slip potential and modify task performance capabilities while working on a slippery surface. The worker- based data from this study will provide guidelines for developing criteria for minimum shoe-lubricant-flooring coefficient of friction and shoe replacement strategy necessary to prevent a slip/fall while wearing worn- out shoes and carrying a weight on a slippery surface.